[rvec] replace malloc/free by operator new/delete

[jblomer]

Replaces #22460
Fixes #22449

[github-actions]

Test Results

    23 files      23 suites   3d 19h 15m 35s ⏱️
 3 852 tests  3 851 ✅ 0 💤 1 ❌
78 483 runs  78 479 ✅ 2 💤 2 ❌

For more details on these failures, see this check.

Results for commit 7dc2ff9.

[silverweed]

Could you please elaborate on why this change fixes the issue?
The wording in the linked Microsoft article is not very clear on C++-style memory allocation, but it does say:

A related problem can occur when you allocate memory (either explicitly with new or malloc, or [...]

Even the LLM's wording on the original issue is vague:

[...] although Microsoft documentation warns that even global new can cause issues if /MD is mismatched, in a uniform project environment where ROOT strictly mandates the dynamic CRT, C++ global ::operator new seems to ensure a more unified heap context under the process heap [...]

So my question is: did you find any docs on why using operator new/delete fixes the issue? Or is it just empirical?

(Same question for @bellenot who maybe is more familiar with Windows specifics)